(CBS/AP) DES MOINES, Iowa - An FBI dive team will be using sonar equipment to search an Iowa lake where the bicycles of Elizabeth Collins and Lyric Cook-Morrissey were found last week in hopes of finding evidence of the girls' disappearance.

FBI spokeswoman Sandy Breault said the team will begin the search at Meyers Lake in Evansdale, Iowa around 6 a.m. Friday. Elizabeth, 8, and her 10-year-old cousin, Lyric, were last seen Friday leaving a house in the Waterloo suburb where their grandmother was watching them.

Authorities stopped draining the lake Thursday because the team's sonar equipment needs at least 6 feet of water to function properly. Prior to the team's involvement, authorities said they would keep draining the lake until Friday.

The dive team is equipped to go into the deepest parts of the lake, which may be as deep as 20 feet.